The present invention relates to an apparatus for observing, for instance, situations of an IC soldered to a printed board with an ultra-small close-up photographing device. More particularly, this invention relates to an apparatus which can be used for not only simply observing an object in an ultramicropore, but also for observing an object in an ultramicropore from various angles by inserting a reflection mirror into the ultramicropore.
An apparatus for observing situations of an IC soldered on a print-circuit board with a ultra-small close-up photographing device is disclosed in German Patent DE 19847913A1. This known apparatus comprises an eyepiece unit (3), an object glass head (2), an image transfer unit (4) for transferring an image photographed by the object glass head (2) to the eyepiece unit (3), and lighting units (15, 1) for illuminating a soldering joint (21) to be checked. The device disclosed is especially in an apparatus for optically checking electric parts arranged on a surface of a print-circuit board (19) or a soldering joint out of sight between electric parts (20) and the print-circuit board (19). The object glass head (2) has a unit (9) for deflecting an image, and the unit extends up to an outer edge of the object glass head (2) in the axial direction. In this apparatus, the lighting units (15, 16) are relatively positioned against the object glass head (2) so that an exit angle of light projected from the lighting units and also transferred through the object glass head (2) is basically equal to a deflection angle caused by the image deflection unit (9) and at the same time the light exit is provided at or near an outer edge of the object glass head (2) adjacent to the image deflection unit (9) in its axial direction.
In the observation apparatus having the configuration as described above, however, as the object glass head (2) approaches a soldered IC during observation, when the IC is arranged singly on a surface of a print-circuit board and there is nothing around the IC, observation is possible. However, if any other IC or other electric parts is provided on the print-circuit board in vicinity to the IC (like in most practical cases), it is impossible to insert the object glass head (2) into a space with the width of only several millimeters between the IC and other parts. In the case as described above, there is no way but to observe the soldering situation of the IC from the diagonal direction keeping the object glass head (2) a little away from the space, so that it is impossible to completely observe the situations of the soldered IC and therefore the result of the observation is not sufficient.
The publication also include descriptions concerning a lighting unit, but the light exit of this lighting unit is provided at or near an outer edge of the object glass head (2) adjacent to the image deflection unit (9) in its axial direction, so that the size of the object glass head (2) is disadvantageously larger.
Further the publication also discloses a light reflection head (23) for illuminating an object to be observed from its behind, but when a silhouette of the observed object being illuminated from its behind, an object positioned inside (or behind) the silhouette cannot be observed.
In the example disclosed in the publication, when it is desired to replace the object glass head (2) with a new one well adapted for observation of an object to be observed, or when the object glass head (2) is damaged, the object glass head (2) can not easily be exchanged with another one or a new one.
In the example disclosed in the publication, a polarizing prism (9) or a polarizing mirror is used to observe an object from the horizontal direction, but if the polarizing prism (9) or polarizing mirror is assembled with low precision due to a small mistake, inaccuracy occurs in polarization and fine adjustment is required, and to evade the troubles as described above, excellent technique and expertise are required in assembling the component.
The present invention has been proposed to overcome the problems as described above, and a first object of the present invention is to provide an apparatus enabling observation of an object in a ultramicropore space.
A second object of the present invention is to provide an apparatus enabling observation of an object in a ultramicropore space by inserting the apparatus in the pore space (between components).
A third object of the present invention is to make it possible to exchange a reflection mirror with another one having the different size or to exchange a reflection mirror, when broken, with a new one.
A fourth object of the present invention is to make it possible to completely observe an object from any angle by illuminating the object at various angles.
A fifth object of the present invention is to give a some degree of allowance in assembly of a reflection mirror so that the component can be assembled by any person not sufficiently experienced in the art.
According to the invention, an apparatus is provided for observing inside of an objection to be observed from a ultramicropore space thereon. In a front side of an object glass, a reflection mirror mounting member spans over a center of the object glass having a flat form. The reflection mirror mounting member projects from right and left. A reflection mirror is mounted at a tip of this reflection mirror mounting member.
A reflection mirror with the size suited to an object to be observed is mounted on a reflection mirror mounting member, and the reflection mirror is faced against a soldering section by bringing the reflection mirror mounting member close to, for instance, a periphery of an IC as an object to be observed on a print-circuit board.
The light for illumination from a light source goes through a bundle of optical fibers and divides to two portions, each of which passes through an optical fiber in the reflection mirror mounting member and further through a reflection mirror holding frame and is projected to the reflection mirror from the light-outgoing edge, and then the light beam is reflected on the reflection mirror, changes its direction by 90 degrees, and illuminates the soldering section.
An image of the soldering section illuminated as described above is refracted by 90 degrees on the reflection mirror, the image light passes along a light axis of the lens system, passes through and is focused by a group of object glasses, a group of internal lenses inside the mirror cylinder, and a group of relay lenses. The focused image is photographed by an ultra small close-up photographing unit and displayed, for instance, on a monitor screen.
It is to be noted that the configuration is also allowable in which a reflection mirror for reflecting the illumination light is not used and light-outgoing edges (illumination heads) of optical fibers are located at any positions around an object to be observed so that the object is illuminated at any angles or from any directions.
When it is desired to observe the soldering section from a different direction, or when an angle of the reflection mirror is not appropriate, any desired correction window at a different range from a light axis of the optical system in the radial direction is selected by driving a reflection mirror angle correction unit incorporated in the optical system to control the incoming light for adjustment.
When the reflection mirror holding frame can be removed from the reflection mirror mounting member, any reflection mirror with the size and angle suited to an object to be observed can freely be selected for use, and in addition the reflection mirror can easily be replaced, when damaged, with a new one.
When inside of a soldered section of an IC is complicated and can not fully be illuminated by the illumination light, illumination heads of optical fibers are unloosened from the bundle and inserted into an ultramicropore space respectively. In that case, as the optical fibers are separated from each other, the illumination heads can enter the inside through the micropore space, and illuminate an area therearound. As the result, by using the illuminating unit with separated illumination heads, it is possible to observe inside of a soldering section which can not be observed with the conventional illuminating unit.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.